doc: add instructions about how to run tests in README

README.md

@@ -6,4 +6,25 @@ This project demonstrates how to use [Vaadin Flow](https://vaadin.com/flow) and
 
 
 ## Running the Application
-There are two ways to run the application :  using `mvn spring-boot:run` or by running the `Application` class directly from your IDE.
+There are two ways to run the application :  using `mvn` or by running the `Application` class directly from your IDE.
+
+
+## Running Tests
+You can run both: Flow and Hilla tests by executing:
+
+```
+mvn verify -Pit,production
+```
+
+For running tests in headed mode run:
+
+```
+mvn verify -Pit,production -Dheadless=false
+```
+
+
+If you prefer run only Hilla tests, just execute:
+
+```
+npm test
+```